The present invention relates to a method and an apparatus for converting a representation of a ventilation duct system, in a computer readable form, from a first duct type to a second duct type, such as circular and rectangular ducts.
Ventilation duct systems, hereafter referred to as ventilation systems, could be constructed with different types of ducts, such as rectangular ducts, circular ducts, oval ducts etc. A circular duct is a duct which has a circular cross-section in which the fluidum (air) flows. Accordingly, a rectangular duct has a rectangular cross-section, etc. Different types of ducts have different properties, and are suitable for different conditions and situations. However, the choice of duct type is primarily dependent on which duct type the constructor and/or the engineer constructing the system is used to work with. Thus, certain duct types are often used, even though they are not the most appropriate
In most cases, the circular ducts are the most suitable. The circular duct elements are quite similar in different systems, and could be provided as standard products, which makes them less costly. Less material are also needed to produce circular duct elements, and less isolation material is needed in case of isolated ducts. Further, the circular duct elements are easier to assemble and mount, and the assembled systems are also. easier to balance. Still further, the circular duct elements are easier to seal, and the generation of noise as well as the pressure loss are less. Consequently, ventilation systems with circular ducts are often to be preferred, compared to systems with rectangular ducts.
It is thus a problem, that many constructors are more comfortable using a certain duct type, e.g. rectangular ducts, in constructing ventilation systems, in spite of the duct type not being the most suitable.
Ventilation systems are nowadays usually constructed by means of software for computer aided design. Conversion between different duct types is possible. However, every duct element has to be converted manually, making the conversion a difficult and tedious task. The connection of the converted elements is also a problem. For this reasons the ventilation systems are usually mounted with the same type of duct elements that are used in the construction design.
There is therefore a need for an easier and more efficient method and apparatus for automatic conversion between ventilation systems with different duct types.
It is therefore an object of the present invention to provide a method and an apparatus for converting a representation of a ventilation system, in a computer readable form, from a first duct type to a second duct type, such as circular and rectangular ducts, overcoming the above mentioned problems.
This object is achieved by means of a method, an apparatus and a computer-readable medium according to the enclosed claims
According to the invention, a method for converting a representation of a ventilation system in a computer readable form from a first duct type to a second duct type, such as circular and rectangular ducts, comprises the steps of:
obtaining an original representation of a ventilation system comprising several straight duct elements and connecting duct elements, connecting said straight duct elements, of the first duct type;
identifying said straight duct elements in the obtained system;
calculating, for each or groups of identified straight duct elements, the equivalent size of one or several duct elements of the second duct type to provide the same performance as said duct elements of the first duct type; and
connecting said duct elements of the second duct type with connection duct elements in accordance with the connection of the corresponding duct elements in the original ventilation system, whereby a converted representation of the ventilation system is obtained.
Hereby, a method, and a corresponding apparatus, is provided for efficient and adequate conversion of a ventilation system with duct elements of a first duct type to a ventilation system with duct elements of a second type. This makes it possible for a constructor used to work with a certain duct type, such as rectangular ducts, to construct systems with this duct type in a computer readable form, where after the ventilation system automatically is converted to a more suitable duct type, without changing the performance and properties of the system. By performance is here meant either that the came fall of pressure, i.e. pressure drop, is obtained for the same flow, or the same fall of pressure is obtained for the same flow velocity.
The conversion according to the invention is preferably made between rectangular ducts and circular ducts, and by use of the expression:
De=C*(W*H)0.625/(W+H)0.250
where De is the equivalent diameter of a circular duct corresponding to a rectangular duct with the width W and the height H, and C is a constant, and preferably about 1.3. An equivalent expression could be used for the conversion from circular to rectangular ducts.
Further, the method preferably comprises the steps of:
defining a maximum height value for the ducts;
comparing the calculated diameter size of the circular ducts equivalent to the rectangular ducts with the maximum height value; and
in case of the diameter being larger than the maximum height value, dividing the circular duct in two or more separate circular ducts with a corresponding total cross sectional area, and each having a diameter less than the maximum height value.
Hereby, the method automatically adapts to a height restriction defined by the user. Such restrictions are quite common, and by the inventive method the problem of circular ducts usually being higher than corresponding rectangular ducts are handled in an efficient manner.
Still further, in the case of a duct being divided in several separate ducts, the connection of the divided duct elements to other straight duct elements in the ventilation system preferably takes place in order of vicinity, whereby the closestducts are connected first. Hereby, the problem of connecting separated ducts is handled efficiently.
The original representation of the ventilation system is preferably created by means of a tool for computer aided design of ventilation systems, and the method according to the invention is further preferably a part of such a tool for computer aided design. Hereby, the method according to the invention could be incorporated in the normal working process, and the need for additional working steps and tools are avoided.
According to a preferred aspect of the invention, the method further comprises the additional temp of searching among available duct elements stored in a database for elements corresponding to the calculated straight duct elements of the second duct type or the connection duct elements, and, if such corresponding elements are found, replacing said element in the ventilation system by the element from the database. Hereby, the ventilation system could be automatically adapted to available standard elements or the like, making the implementation of the system easier and more efficient.
The invention further comprises an apparatus to execute the inventive method, as well as a corresponding computer-readable medium comprising a program tool with instructions to perform the steps according to the invention.